File size: 1,138 Bytes
064bfd6 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | import { lineWidth } from './line-width-cache.js'
type Output = {
width: number
height: number
}
// Single-pass measurement: computes both width and height in one
// iteration instead of two (widestLine + countVisualLines).
// Uses indexOf to avoid array allocation from split('\n').
function measureText(text: string, maxWidth: number): Output {
if (text.length === 0) {
return {
width: 0,
height: 0,
}
}
// Infinite or non-positive width means no wrapping — each line is one visual line.
// Must check before the loop since Math.ceil(w / Infinity) = 0.
const noWrap = maxWidth <= 0 || !Number.isFinite(maxWidth)
let height = 0
let width = 0
let start = 0
while (start <= text.length) {
const end = text.indexOf('\n', start)
const line = end === -1 ? text.substring(start) : text.substring(start, end)
const w = lineWidth(line)
width = Math.max(width, w)
if (noWrap) {
height++
} else {
height += w === 0 ? 1 : Math.ceil(w / maxWidth)
}
if (end === -1) break
start = end + 1
}
return { width, height }
}
export default measureText
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